A device of the type in question, and an associated method of the type in question are known from EP 1 017 554 B1.
Conventional methods for producing concrete blocks, and in particular paving stones, building blocks or the like, provide, in most cases, a basic body which is formed from coarse concrete, and is then provided on the upper side with a solidly covering facing layer of colored concrete or concrete mortar. In this case, provision is made for the coarse concrete to be poured into a mold and compacted in the mold by shaking and/or pressing. This causes the coarse concrete to sink. In the lowered space of the mold, the colored concrete mortar is then applied to the coarse concrete as a facing layer and compacted from a storage container which is also referred to as the facing container or facing silo.
It is known to use gravity to remove from the storage container dyed concrete or concrete mortar as a facing layer for concrete blocks. In the case of a multicolored facing layer, for example, if a marbled facing layer or a color mix is to be achieved, concrete or mortar masses are introduced into the storage container, separately, color by color, and then supplied to the molds in a blended, or unblended form.
Furthermore, it is known to use for each colored concrete its own additional container from which the desired amount of concrete is dispensed in each case.
The described methods and devices have in common the drawback of high machine and production-related costs. In addition, many of the facing layers which are achieved display undefined color patterns as a result of disadvantageous blendings, for example as a consequence of heap formations.
A storage container forming a receiving space for a plurality of layers of different-colored concrete is known in the general art. In this regard, the floor of the storage space is typically embodied as a slide. Once the storage space has been filled with the various layers of concrete, the slide is opened continuously or cyclically, so that gravity causes partial amounts or portions of the enclosed layers to fall downwardly and then be supplied to a downstream release device. The downstream release device can have a closure member which is embodied for controlling a quantitative, portionwise release of the colored concrete, or concrete mortar, and which then fills the molds. The configuration of the storage container with a slide causes only comparatively low machine costs, and leads to improved through-mixing of the layers of different-colored concrete. Nevertheless, the blending of the layers of different-colored concrete is not yet sufficiently advantageous. Further heaps are in particular formed. This applies in particular to the first partial amount that falls downwardly when the slide opens. For this first partial amount, only a slight amount or insufficient blending typically takes place.
In order to further improve the blending, the generic document, EP 1 017 554 B1, proposes combining the slide known from practical experience with impact bodies arranged in the path of movement of the partial portions of the concrete layers that move downwardly as a result of gravity. In this case, the partial portions of the concrete layers are intended to strike the impact bodies in such a way that the partial portions are guided onto a deflecting curve and blended with one another more effectively.
The solution known and taught from EP 1 017 554 B1 further improves blending, but leads to higher machine and design costs. In addition, there is also the problem that, in particular, the first partial amount of concrete or concrete mortar that is let out through the slide displays a disadvantageous blending. The blending is improved only over the course of the further letting-out of partial portions of the layers. However, as the receiving space of the storage container has only a limited size, paving stones with a facing layer displaying a color blending which is different to, i.e. less advantageous than, the remainder of the batch are produced frequently, that is to say whenever the first partial amount is let out of the storage container.